The current state of the art of gas guns involves the compression of a propellant gas, usually a light-gas, such as helium, prior to introduction thereof into the gun chamber. Because all propellant gas is introduced through the rear of the gun chamber at the breech end of the gas gun, relatively high gas temperatures and peak pressures must be developed to accelerate a projectile to high velocities. This is because the initial gas pressure decreases rapidly and cannot be maintained as the projectile travels down barrel. As such, compression of the propellant gas generally requires the use of an explosive material, such as gun powder, acting on a piston.
When using conventional gas guns, the shot is not controlled beyond the initiation of a primary stage and if an undesirable projectile acceleration is occurring within the gun barrel it cannot be corrected during the shot. As a consequence, obtaining a desired projectile velocity generally involves trial and error.
In view of the above, it would be advantageous to provide improved gas gun devices and methods for accelerating projectiles. For example, it would be advantageous to provide gas gun devices and methods offering the acceleration of projectiles to desired high velocities at lower peak gas pressures and temperatures. Additionally, it would be advantageous to provide gas gun devices and methods that offer the ability to control the acceleration of a projectile as the projectile is accelerated.